Discussions By Condition: I cannot get a diagnosis.

Joint Pain with Rash

3 weeks ago I developed an itchy rash all over my body (arms, legs, palms of hands, scalp, and a little on the face) that seemed to be an allergic reaction to something. I had pain and swelling in my joints. No fever, no signs of infection or bug bite. I went to the hospital where they prescribed Prednisone. The rash got better, but then 2 days later it came back, again covering my body. I went to the hospital again, where they described my rash as "weals" and concluded that it must have been an allergic reaction to an unknown substance. They put me on a higher dose of Prednisone, and after 4 days in the hospital the rash and swelling was gone, I just had a little joint pain. I tapered of of Prednisone (60 mg for 3 days, 40 mg for 2 days, 20 mg for 3 days, 10 mg for 2 days...). I went to see an allergist who did an allergy test that came back completely negative. 3 days later the joint pain came back and has since then, about a week ago, gotten worse. I am also experiencing some skin numbness on my shoulders, face, chest, calf, and foot. This numbness is not the same on both sides of the body. I went to the emergency room 2 days ago for the joint pain and they did not even have a guess as to what is causing my symptoms. They did blood work and said that I do not have an infection. They said I should follow up with a rheumatologist.

The week before I got the rash, I had upset stomach, diarrhea, pain with urination, and cloudy urine (I figured it was an UTI). My dentist also recently told me that my teeth were decalcifying even though I don't drink soft drinks and rarely eat candy. I also have several canker sores on the tip of my tongue. I am not sure how much of this is relevant, but I figured I should list every possible symptom since nothing seems to make sense with this.